Johnson Carburetor Cleaning (1hp to 40 hp) 1989-2005

A carburetor is a device attached to Johnson outboard internal combustion motor and it’s designed to mix air with a fine spray of gasoline. On occasions, a Johnson outboard carburetor will get dirty and need to be cleaned to make it free of dirt, marks or messes.

Cleaning a Johnson carburetor involves removing it from the engine, disassembling it, and cleansing it or wiping it free of grime using a cloth, compressed air or with a brush. This guide describes the process of how to clean a Johnson outboard carburetor.

Carburetor Cleaning

The carburetor must be removed from the engine and disassembled before it can be cleaned. Once disassembled, use a clean bristle brush to remove varnish deposits, dirt and grime. Use Carburetor and Choke Cleaner to wash all components clean.

IMPORTANT: Never submerge Johnson outboard carburetor or it’s components in a hot soaking tank or submerged in a strong carburetor cleaner. Strong carb cleaners have a tendency to remove critical sealing compounds and can even damage components.

Use a small syringe filled with isopropyl alcohol to to flush carburetor passages and holes. Use compressed air to blow the carburetor and its passages dry. The compressed air should not reach more than 25 psi (172 kPa). When using the compresses air to dry passages, make sure the air flow is traveling in the opposite direction of fuel flow.

IMPORTANT: Never use a small drill bit or wire to clean the carburetor jets and orifices.

Carburetor Inspection

Inspect the body of the carburetor and the top cover. Visually check for damage or cracks. If damage is found on any components, replace it with a new part. If the body of the carburetor is worn, replace that too.

Inspect the carb’s needle valve seat.

Inspect carburetor’s jet and nozzle.

Visually inspect the needle valve assembly. If worn or broken tips are discovered, replace the assembly.

Connect the auto-enrichener positive and negative leads to a 12 V battery so as to check that the PTC heater area is heats up. The PTC heater should heat up within 5 minutes of being connected to the 12V battery.

IMPORTANT: The auto-enricher is not a serviceable part. Do not attempt to disassemble the auto-enrichener.

Never attempt to remove, disassemble or clean the Johnson outboard carburetor without the assistance of a repair manual. Additional specifications and cleaning procedures might be listed in the manual.